Facile synthesis of manganese oxide-embedded mesoporous carbons and their adsorbability towards methylene blue

Herein, a facile strategy to fabricate the novel manganese oxide-imprinted mesoporous carbons (MOPCx, x presents for pyrolysis temperature) was described via the direct pyrolysis of Mn2(BDC)2(DMF)2 (BDC = 1,4–benzenedicarboxylate, DMF = N,N–dimethylformamide) as a self-sacrificed template at various temperatures (x = 550, 750, and 950 °C). The characterization results demonstrated the existence of MnO embedded in carbon structures with different morphologies, and enhancing surface areas (249.86–294.67 m2/g) compared with their precursor (3.59 m2/g). For methylene blue adsorption experiments, the MOPC pyrolyzed at 950 °C (MOPC950) revealed the best candidate with maximum uptake capacity (124.1 mg/g), so far higher than other MOPCx and Mn2(BDC)2(DMF)2 materials. Finally, adsorption mechanisms involving H-bond, and π–π interaction were proposed via the chemisorption between surface functional groups (carboxyl, phenol, lactone, and base). [Display omitted] •Novel MOPCx nanomaterials were facilely synthesized under various temperatures.•Kinetic and isotherm of methylene blue adsorption onto MOPCx were investigated.•Surface functional groups on MOPCx play a crucial role in methylene blue adsorption.•MOPC950 reached the highest Qm value, at 124.1 mg/g.